MASTER'S THESIS
Tool Belt for Pro Users Development of an Ergonomic and Robust Tool Belt
for Professional Forestry Workers
Linnea Wykman 2015
Master of Science in Engineering Technology Ergonomic Design and Production
Luleå University of Technology Department of Business Administration, Technology and Social Sciences. Acknowledgement I would like to start off by thanking the Director of Primary & Concept Development, Johan Hallendorff at Husqvarna Group for giving me this project for my master thesis. I could not have gotten a better project, it was interesting, I got to work with something of real value for the company and I was privileged to collaborate with great people like the brand manager for the Husqvarna brand Rajinder Mehra.
I want to thank the engineers at the department of Primary & Concept Development for making me feel welcomed and included as if I was one in the team. You were all intelligent hardworking and genuine people and I enjoyed talking to each and every one of you. To Eric Lennings my supervisor at the company and the department I would like to say that I was very lucky to get to have you as my supervisor. You were encouraging, always giving me tips and even when you had a lot on your plate and I asked you for a little bit of help you always met me with a big smile.
For everyone that took part in my benchmarking and usability testing’s I must say that I was surprised of how dedicated you all were. The testing’s took longer than I had expected because you all took your time to really give me the most accurate result in the tests that you could possible give me. So thank you all for that, you were all very helpful with what was a very important part of my project.
I also want to thank Alexander Persson Product Management and Specialist at Accessories for Husqvarna Group for being there and helping me in this project, with material that I needed to make my prototypes and when I had questions.
To Åsa Wikberg-Nilsson my supervisor at Luleå University of Technology. I can’t thank you enough for all of your effort. Guidance in my thesis and your amazing support in everything. I felt that you went over and beyond the task of just supervising.
I met a lot of people in this project and I felt that I got treated extremely well and that everyone was very helpful. I don’t have room in this section to thank you all but I wish to express my gratitude to everyone that helped me.
Luleå 28th of June, 2015
Linnea Wykman
Abstract This report covers the entire development process for a new ergonomic and robust tool belt for Husqvarna Group. The objective of this project was to develop a new tool belt concept and produce five belts to be tested in the field by the target group of the belt: the professional forestry workers.
The work consisted of identifying what makes the belt ergonomic for the application and a materials selection process. To produce a belt that visually advocates the Husqvarna brand a collaboration with the Husqvarna brand manager was essential.
The information that the development of the belt been based upon was by studying the environment and how the product is used by professional forestry workers. This has been carried out through interviews, literature studies, observations and importantly that the responsible of this project has experienced the environment and also performed the forestry work that the belt is used for.
The actual shape of the belt has partly been developed through a series of usability tests, where a group of civilians and users of forestry belts got to try out and evaluate competitors' belts, where both forestry and carpenter's belts been included. Similarly this group also evaluated prototypes based solely on the shape of these belts, all made out of the same material. Finally professional forestry worker got to evaluated prototypes of six different concepts.
The most ergonomic shape was developed partly based on the collected information, the shape of the two belts that got the best results in usability testing’s and on human anatomy and physiology.
Interviews and meetings with manufacturers and suppliers was conducted to obtain knowledge about materials such as textiles, foams, plastics, and webbings. The most suitable material for the belt were selected accordingly to the requirement list.
KEYWORDS: Product development, Ergonomics, Tool belt, Forestry work.
Sammanfattning Den här rapporten behandlar hela utvecklingsprocessen för framtagning av ett nytt ergonomiskt och robust verktygsbälte för Husqvarna Group. Målet med arbetet var att utveckla ett nytt koncept och producera fem stycken bälten, för att testas i fält av målgruppen för arbetet: professionella skogsarbetare.
Arbetet har bestått utav att identifiera vad som gör ett bälte ergonomiskt för tillämpningen och materialval. För att ta fram ett bälte som visuellt uttrycker Husqvarnas varumärke har ett samarbete med Husqvarnas brand manager varit väsentligt.
Informationen som utvecklingen av bältet baserats på har varit att undersöka miljön och hur produkten används av professionella skogsarbetare. Detta har utförts via intervjuer, litteraturstudier, observationer och att ansvarig av detta projekt fått uppleva miljön och själv utföra de moment i skogsarbetet som bältet är avsett för.
Själva formen på bältet har delvis tagits fram genom en rad användartester, där en grupp bestående av civila och användare av huggarbälte fått prova och utvärdera konkurrenters bälten, där både huggarbälten och snickarbälten ingått. På samma sätt har denna grupp fått utvärdera prototyper, alla i samma material, som baserats på enbart formen av dessa bälten. Slutligen har professionella skogsarbetare utvärderat sex olika koncept.
Den mest ergonomiska formen på bältet togs fram baserad delvis på tidigare informationsinsamling och på formen av de två bälten som fått bäst resultat i användartester samt människans anatomi och fysiologi.
Tillvägagångsättet för att ta reda på vilka material såsom textilier, skum, plaster, och remmar, som är lämpliga för bältet har bestått av intervjuer och möten med tillverkare och leverantörer. Detta för att ta del av deras kunskaper för att sedan avgöra vilka material som enligt kravspecifikation är mest lämpliga att använda i bältet.
NYCKELORD: Produktutveckling, Ergonomi, Verktygsbälte, Skogsarbete.
Content
1 Introduction ...... 1 1.1 BACKGROUND ...... 1 1.2 STAKEHOLDERS ...... 3 1.3 PURPUSE AND GOAL ...... 4 1.4 PROJECT SCOPE ...... 4 2 Context...... 5 2.1 THE CLIENT COMPANY ...... 5 2.2 THE PRO USER ...... 6 2.3 THE ENVIROMENT ...... 6 2.4 HAZARDS OF FORESTRY WORK ...... 7 3 Theoretical Framework ...... 9 3.1 ERGONOMICS ...... 9 3.2 ERGONOMICS IN PRODUCT DESIGN ...... 10 4 Method and Implementation ...... 12 4.1 PROCESS ...... 12 4.2 PLANNING ...... 12 4.2.1 The brief...... 13 4.2.2 Gantt chart ...... 14 4.3 COLLECTING INFORMATION ...... 16 4.3.1 Experiencing prototyping ...... 16 4.3.2 Interviews ...... 17 4.3.3 Husqvarna’s current belts ...... 20 4.3.4 Think-Aloud Protocol...... 20 4.4 BENCHMARKING ...... 22 4.4.1 Benchmarking brands ...... 22 4.4.2 Benchmarking shape and ergonomics -experiencing form ...... 23 4.4.3 Summary of benchmarking and think-aloud ...... 24 4.5 LITTERATURE REVIEW ...... 25 4.6 PRODUCT REQUIREMENT LIST ...... 25 4.7 IDEA DEVELOPMENT ...... 27 4.7.1 The Scamper technique ...... 28 4.8 SEARCHING FOR WORKING PRINCIPALS...... 29 4.8.1 Textile tool belt ...... 29 4.8.2 The current Husqvarna belt ...... 29 4.8.3 Husqvarna’s harness for forestry clearing saws ...... 30 4.9 CONCEPT DEVELOPMENT ...... 31 4.9.1 Prototyping ...... 31 4.9.2 Construction of the belt ...... 32 4.9.3 Exploring alternatives for ventilating properties ...... 33 4.9.4 Materials in context ...... 34 4.9.5 Innovation Expo in November, 2014 ...... 34 4.9.6 Iterating experiencing prototyping ...... 36 4.9.7 Computer modeling ...... 37 5 Results ...... 40
5.1 CONTEXT RESULTS ...... 40 5.2 RESULTS OF IDEA AND CONCEPT DEVELOPMENT ...... 41 5.3 RESULTS OF DETAIL DEVELOPMENT...... 41 5.4 FINAL RESULT ...... 41 Discussion ...... 44 5.5 RELEVANCE ...... 45 5.6 RECOMMENDATION ...... 46 References ...... 49 Appendices Appendix 1 – Project brief Appendix 2 – Project time plan Appendix 3 – Materials and companies Appendix 4 – Benchmarking brands Appendix 5 – Benchmarking shape and ergonomics-experiencing Appendix 6 – Iretating experiencing prototyping Appendix 7 – Textiles for the outside Appendix 8 – Textiles for the inside Appendix 9 – Foams and 3 mesh spacer fabric Appendix 10 – Construction upholding materials Appendix 11 – 3 mesh spacer fabric Appendix 12 – TPO Appendix 13 – Webbings
List of figures Figure 1. Current tool belt and attached holsters. Figure 2. Brass screws. Figure 3. Old belt buckle solution - open. Figure 4. Old belt buckle solution - closed. Figure 5. Solution for attaching holster that will be used for the current belt. Figure 6. Solution for attaching holster. From Gustafsson & Karlsson (2014). Figure 7. Display of Husqvarna Group products. Figure 8. The professional worker. Figure 9. Illustrating biomechanics calculations. From Bohgard et al. (2011). Figure 10. Ergonomic product development process, according to Haubner (2007). Figure 11. The project brief (also found in appendix 1). Figure 12. Gantt chart used in project (also found in appendix 2). Figure 13. A visual representation of the time spent on different parts in the project. Figure 14. The author limbing a tree, during experience prototyping. Figure 15. Visit at F.O.V Fabrics AB for material selection. Figure 16. Elmia subcontractor fair, visited in autumn 2014. Figure 17. Holster from Husqvarna. Figure 18. Wide belt from Husqvarna. Figure 19. Normal waist belt from Husqvarna. Figure 20. Competitors belts used in think-aloud session. Figure 21. Competitors belt from benchmarking activity. Figure 22. Shape of belts that were tested in benchmarking. Figure 23. Illustrates the prototypes of belts that were tested in the benchmarking activity. Figure 24. Product requirement list Figure 25. Illustrating the two belts that got best test results. Figure 26. Illustrating human anatomy and the fit of the belt. Figure 27. Ideas from using the Scamper method. Figure 28. Illustrating the working principle of the Snickers XTR belt. Figure 29. The wide Husqvarna belt. Figure 30. Illustrating the Husqvarna harness and the belts fabric. Figure 31. Illustrating the belt prototypes. Figure 32. Illustrating the conical belt. Figure 33. Illustrating the edges of the belt and how the different materials can be sewn together (in Swedish). Figure 34. Illustrating different ways to create ventilating channels. Figure 35. The visual appearance and material suggestions of the final belt design, developed by the Husqvarna brand manager. Figure 36. The final prototype made for the Innovation Expo in November, 2014. Figure 37. The author with the final belt design at the Innovation Expo. Figure 38. Illustrating new experience prototypes. Figure 39. Illustrating the working prototypes. Figure 40. The belt design was modeled in 3D. Figure 41. Illustrating the 2D drawing of the belt. Figure 42. Illustrating the modeled Tool belt design Figure 43. The final Tool belt design. Figure 44. Illustrate the foam laminated TPO material Figure 45. Illustrate the textile laminated 3 mm PE foam used in the belt to make it comfortable. Figure 46. Illustrates the concept of attaching holsters. Figure 48. Images illustrating the belt’s detail designs, and the final design "in action". Figure 49. Illustrates the Techsteel material Figure 50. Illustrates a reflective material.
1 Introduction This master's thesis concerns the development of a new tool belt used in professional forestry work for the company Husqvarna Group. The forestry worker uses a belt to carry necessary tools while felling and handling trees. The brief from the Husqvarna Group states that the current belt does not fulfill customer needs, the product is experienced as outdated and there is a need for a more adjustable and functional product.
The master thesis project, hereafter referred to as the project, has been executed on site at the client company in Husqvarna, Sweden, at the Department of Primary and Concept Development. The project was carried out during the autumn semester of 2014, by one master thesis student in Industrial Design Engineering/Ergonomic Design and Production, from Luleå University of Technology. The exam work was performed as a 20 weeks project of 30 credits.
1.1 BACKGROUND To remain in the forefront of the market and potentially increase sales Husqvarna Group wants to come up with a new and updated tool belt for professional forestry workers. The current tool belt was developed in the 1980s and very few changes have been made since. The tool belt is used for motor manual work with a chainsaw for timber cutting operations such as cutting, limbing, bucking and bunching of trees.
The forester uses certain tools while working in the field. The belt used today has holsters attached for carrying tools and accessories. The current Husqvarna belt, se figure 1, uses screws, se figure 2, to attach the holsters. Attaching the holsters with screws is problematic for several reasons. Handling the screws is time consuming and extra tools are needed just for the screws. The screws can easily be lost in the field and the forester therefore needs to carry spare screws (Gustafsson & Karlsson, 2014).
Figure 2. Brass screws. Figure 1. Current tool belt and attached holsters.
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Prior to this project, an extensive market analysis has been executed, and a new more easy and adjustable solution for attaching the holsters was developed. This also included how detachable braces can be attached to the belt. This was the exam work of two bachelor students in the Mechanical Engineering program at Jönköping University School of Engineering, in the subject area of product development (Gustafsson & Karlsson, 2014). The analysis extended from identifying the customer’s needs through field studies and interviews with different users, to a solution of the holster attachment problem. It was also discovered during contact with users that many of them wanted the previous version of the belt buckle to be reintroduced (Gustafsson & Karlsson, 2014). The old solution is an extendable belt buckle and have two settings when the belt is worn. When the belt buckle is closed, see figure 3, the belt fits tight and when the belt buckle is open, see figure 4, the belts will fit a bit looser. While working the forester need the belt to have a tight fit but if the forester needs a break he can easily open the extendable belt buckle and get loser fit. The appreciation for the old belt buckle solution came from having these two settings for the belt and how easy it is to shift between them.
Figure 3. Old belt buckle solution - open. Figure 4. Old belt buckle solution - closed.
The new solution developed in the prior project will make the holsters easy to change, so that that the belt can be used for other work assignments in the forest too, such as planning work, including marking of trees with marking spray and using flagging tape to mark areas of the forest. This requires holster for the flagging tape and marking spray. This belt solution will be much more flexible and easy to customize for different work assignments (Gustafsson & Karlsson, 2014). The new concept, see figure 5, uses a lower strap to hang the holster on. To secure the holsters another strap is folded over the lower strap and attached by snap fasteners. The previous concept had holes in the lower strap and the holsters had flies to go true this holes, see figure 6; the purpose for this was to make sure that the holsters stayed in place. In a meeting with the Director of Primary & Concept Development, Husqvarna Group and the company supervisor, it was decided that the solution with holes in the lower strap wasn’t necessary and to instead exclude the holes in the lower strap, see figure 5.
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Figure 5. Solution for attaching holster Figure 6. Solution for attaching holster. that will be used for the current belt. by Gustafsson & Karlsson (2014).
What remains to be developed in the current project is the belt itself. The client company wants the following issues to be addressed:
. Developing a belt that is ergonomic . Identification of what material to use . A new and “sharper” design
This is the scope of the project. Older holsters from Husqvarna will not be compatible with the new belt; hence new attachment system were new holsters must also be developed.
1.2 STAKEHOLDERS The project was executed at the Department of Primary and Concept Development for Husqvarna Group. The department is responsible for developing new product ideas and concepts for Husqvarna’s handheld products. The department build knowledge in a number of strategic areas and operates sub- projects within these areas, with the goal of finding new innovative solutions.
The tool belt product belongs to the section of Husqvarna group called Accessories that provides protective clothing, spare parts and other accessories. The client that made the request for a new tool belt is a product management specialist at Accessories for Husqvarna Group. The target group for the new tool belt have forestry work as a profession and are specialist in their field. The current customers are from Europe, North America, Russia and Asia. The target group have high demands and only use the best equipment on the market.
3 1.3 PURPUSE AND GOAL The main objective of the project is to develop a tool belt in-house for the Husqvarna brand. A sub-supplier makes the current belt that is on the market, and Husqvarna has little influence to develop a better belt by using this supplier. By having the product made in-house, there will be no middleman. Also, by developing a tool belt that is better than the competitor’s belts, Husqvarna expects the sales to go up. The aim for this project is to start from Gustafsson and Karlsson’s (2014) prior work with the belt, use the modified concept for attaching holsters, and develop a new conceptual belt design. This include collaboration with the engineers at the Husqvarna Department for Primary and Concept Development, in order to develop a new version of the old belt buckle to fit the new belt concept. It also involves to select all the materials the belt are intended to include, and to develop the industrial design, such as shape, function and the construction of the belt. Also, it involves collaborating with the Brand Design Manager for the Husqvarna brand during development of the visual appearance of the belt, so it will fit and be in line with the Husqvarna corporate identity. In the end of the project, five functional prototypes of the new tool belt shall have been professionally made. These prototypes will later be tested in field by professional forestry workers and evaluated by Husqvarna. The main aspects of the project are:
. The ergonomic aspects . The materials selection . The visual appearance . The construction of the belt
The ergonomics include comfort, a shape that distribute the weight over the hips and back in an ergonomically purposeful way and also that the belt is functional and enable performance. The visual appearance shall appeal to the target group, fit the brand and complement the range of protective gear and clothing for the professional forestry worker. The material selection process will involve contacting companies that manufacture materials and suppliers that is of interests for the belt, have them ship the materials to Husqvarna and later decide what materials to use by choosing the material that best fit the requirement for the belt.
1.4 PROJECT SCOPE The project concerns the development of an ergonomic belt and the choices of materials for the belt. An engineer at Primary & Concept Development will develop the extendable belt buckle in collaboration with the Design Department for the Husqvarna brand. The outline such as color disposition for the visual appearance for the new belt were set by the Brand Design Manager for Husqvarna group. Some changes in the visual appearance were made to better match the result from the requirements from customer demands and also available colors in the fabric for small orders affected the resulting appearance.
4 2 Context In order to understand the conditions that existed from project start, the context was studied thoroughly. This chapter includes a brief introduction to the client company, a description of the target group, the environment that the forestry workers are exposed to, and the hazards of forestry work.
2.1 THE CLIENT COMPANY Husqvarna Group is the world's largest producer of outdoor power products including robotic mowers, garden tractors, chainsaws and trimmers (Husqvarna Group, n.d.). Husqvarna and Gardena are core brands. Husqvarna has long been a strong global premium brand for professional users and consumers who demand high performance. The brand stands for technological leadership, professional performance, high quality and user focus (Husqvarna Group, n.d.). Gardena is the leading premium brand in Europe for watering products and garden tools for consumers.
Husqvarna Group also have a number of regional brands, examples are Jonsered, McCulloch and Klippo, and these brands hold strong positions in local markets or within specific product categories.
Along with power products the Husqvarna chainsaws user can buy all of their protective equipment like safety trousers, safety boots, helmet with visor, hearing protection, gloves and the forestry tool belt from the Husqvarna brand.
Figure 7. Display of Husqvarna Group products.
5 2.2 THE PRO USER The following description of the target group, the Pro user, comes from the client companys internal material. The professional forestry worker are described as people who are experts and work as specialists for a forestry company or as a contractor. Today, they are almost always men, but this is not a limitation for the project. Also, farmers and landowners that are making a living out of their forests can be included in the Pro user group. As an expert that work full time in the forest, the worker need high performance equipment that are reliable and durable enough to ensure a high run time, and can work effectivly without failure. Figure 8. The professional worker.
This group spend money on high performing and quality chainsaws, accessories and safety equipment. They tend to be brand loyal, and buy all equipment, clothing, tool belt, saftey helmet, boots, gloves and underclothing from the same brand. The credibility and trustworthiness of the brand is described as important, as well as that the brands’ products are developed for professional workers needs and demands. The harsh environment that they are working in demand for highly robust products. Problems and failure of equipment, i.e. when they can’t do their work, means loss of productivity, which is described to be expensive and also to create irritation.
The Pro user does not compromise quality, but the style is also described as a consideration. They are experts in their field, they use only the best chainsaws, they like to show skill and confidence and look the part, with the premium brands line of clothing that is stylish and that visually communicates heavy duty business. Safety is described as of extremly high importance. Innovations and new features are of no interest for them, unless they create real user value. The Pro user group invests in premium tools and equipment, they are described to use the brand for years, and they continuously replace chainsaws and other equipment.
2.3 THE ENVIROMENT In the beginning of the project, a field study was performed. It resulted in an understanding of the environment in which the final solution is supposed to be used. The following text is the author’s own analysis of the environment,
6 with a base in semi-structured interviews with forestry workers but also origins from the market analysis of Gustafsson and Karlsson (2014). The environment the belt is subject to is harsh. It is important to understand what the belt will be exposed to when developing and constructing a belt that can endure the demands of the environment. When cutting the tree with a chainsaw, matchwood resin and dirt releases and flies in full speed against the worker. Some materials are unsuitable for forestry work. Matchwood and resin get stuck in Velcro tape and it loses its attaching properties. Also fabric like meshes used for its ventilating properties will get full of matchwood.
The overall construction and combination of materials must be well thought through. Forestry work requires a belt of high quality and robust materials. It must be UV-resistant, withstand water and not get stiff in cold temperatures. Forestry worker sometimes leaves the belt outside over the night, so it is important that the belt does not absorb water. If the belt is wet and is difficult to dry up, it may mold. Also it can be good if the color of the belt stands out, i.e. that it does not melt in with the environment.
2.4 HAZARDS OF FORESTRY WORK Forestry and logging work is highly demanding, and it is probably one of the last heavy physical jobs left in the industrialized world (Åstrand & Rodahl, 1988 cited in Gallis, 2006). The profession is also said to be among the most affected ones, when it comes to fatal injuries, mainly caused by motor manual felling (Swedish Work Environment Authority, 2012). Modern forest work can be divided into two categories: motor-manual work, often with the use of chainsaw or other mechanized tools and secondly, the mechanized forestry work, with the use of heavy machinery (Harstella, 1990). Depending on the terrain and type of forest, more or less manual work must be carried out with chainsaw, but mechanized forestry stand for most of the harvesting. Small-scale forestry driven for example by farmers are usually performed as motor-manual work. Government regulations in Sweden require the use of safety gear while working in the forest: working with a chainsaw requires hearing protection, safety helmet, eye and face protection, protective boots, protective gloves and leg protection (Swedish Work Environment Authority, 2012).
Motor manual timber cutting operations such as cutting, limbing, bucking and bunching of trees with chainsaws has been mentioned as physically very strenuous work (Gallis, 2006); the physical strain on the cutters is caused by both heavy lifts and high-energy expenditure. According to Harstella (1990), heavy physical work generally has an increased risk for injuries in the musculoskeletal system; one of the more dominant health problems is various forms of back pain. In a study made in Sweden (Pontén, 1988 cited in Gallis, 2006), 3600 chainsaw operators were studied for musculoskeletal problems. Out of every ten workers, five had complaints in lower back area; two shoulder complaints, two knee complaints, and two hip complaints. In summary, rest and maintaining a good working posture is very important for the workers 7 health, since musculoskeletal disorders are so common among forestry workers. Heavy lifting is a clear risk factor and the risk of injury increases with twisted and/or forward curved posture. Already the handling of moderate burdens result in very high forces on the disks, according to Gallis (2006).
8 3 Theoretical Framework This chapter contains the knowledge that the current work has been built upon. It involves theories of ergonomics and how this can be implemented within product design.
3.1 ERGONOMICS Over the last 50 years the field of human factors or ergonomics has evolved into an independent discipline that focus on the interaction between human and technology (Dul, 2008). The formal definition approved by the International Ergonomics Association, reads as following:
“Ergonomics (or Human Factor) is the scientific discipline concerned with the understanding of interactions among humans and other elements of a system, and the profession that applies theory principles, data and methods to design in order to optimize human well–being and overall system performance (IEA, n.d.).
Usually in terms of ergonomics it is the human interaction with the surroundings in terms of force torque and mechanical energy that is considered (Bohgard et al., 2011). Biomechanics is a discipline that applies the physical laws of mechanics on to the human body. Biomechanical analysis is often used to evaluate manual work and how forces acts on structures in the human body while, lifting pushing carrying or pulling (Bohgard et al., 2011). Manual lifting is still needed in the industrialized world and it can be acceptable if it satisfies certain ergonomic requirements. NIOSH is a method to assess lifting situations and is developed by the American National Institute for Occupational Safety and Health (www.cdc.gov/niosh). The following example is from Bohgard et al. (2011): For example if a person, se figure 9, is lifting a box that weighs five kilos. When calculating the compression force on the lower back the result in the first case is 320 kg and in the second case it is 440 kg. The recommended limit from NIOSH for the compression force on the lower back is 340 kg. In the second case the force is 100 kg higher than the recommended value. This means that in the second posture the compression force is almost 9 times higher, than the weight of the burden.
This example illustrates how a bad posture and somewhat low loads can result in high-localized mechanical stresses that overtime lead to pain in various body parts. This strongly indicate that forestry work where bad postures are unavoidable and loads they carry are much heavier than a 5 kilo box will exceed the limits set by NIOSH. A summary is that this makes forestry work a hazardous field to work in and that musculoskeletal problems will probably appear over time.
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Figure 14. Illustrating biomechanics calculations. From Bohgard et al. (2011).
3.2 ERGONOMICS IN PRODUCT DESIGN To be successful at optimizing the ergonomic quality of the product the ergonomic aspect must be systematically applied and be embedded throughout the product life cycle (Haubner, 2007). Haubner suggests that the aspect of ergonomic plays an important role in the early stages of product design, for the assurance of ergonomic quality. The main tasks to solve in ergonomic industrial design according to Haubner are:
. Analysis and description of the user characteristics and system tasks . Design of usability concept and user interfaces . Ergonomic evaluation of prototype solution variants
The development process of products exhibits various phases and activity’s the schematic representation in following sections represent essentially the five phases of any product development process. The type of product or system determents the content of each phase (Haubner, 2007).
DEFINITON
CONCEPT
REALISATION
EVALUATION
APPLICATION
Figure 10. Ergonomic product development process, according to Haubner (2007). 10
According to Haubner (2007), the main emphasis in traditional product development processes are placed on the technical functionality and on technical features, rather than on the tasks and needs of potential users. Therefore, mistakes in design often are uncovered relatively late. A proceeding in this manner means that changes, if at all possible, will according Haubner be very time consuming and costly. This is why Haubner stresses that is so important to include the ergonomic aspects into the various phases of product development.
11 4 Method and
Implementation
This chapter presents the entire process of the project. The methods that have been used is presented and how they have been implemented to achieve what is later presented in the chapters of result and discussion. The methods that have been used are specifically chosen for the topic of the report whit focus on how to achieve an ergonomic design. This have also led to answering the question of what is an ergonomic design for this product. Many of the methods used to achieve this has simply been by evaluating the product by testing it on the user, prototyping and iteration.
4.1 PROCESS The product design process follows a structured flow of activity’s, which in turn generates a flow of information to the project (Österlin, 2011). In general, according to Österlin; to follow a process secures that the industrial designer clarifies the relationship between the product and the user; the human. For product planning, Österlin means that the degree of the novelty of the task determents the layout of the planning phase for the task. For the development of the product in this project, the task can be categorized as an adaptive design, which means that the solution principle remains unchanged, and only the embodiment is adapted to new requirements and constraints.
The current project consisted of five segments: 1) the planning, 2) gathering of information and analysis, 3) concept and idea development, 4) processing and 5) the follow up. The sub structure of each segment was adapted to the product and the objective of the project. The design process is the key in industrial product design (Österlin, 2011). The user needs and product demands needs to be clarified. In product design two main areas exists: one is to develop product to adjust the product in a broad sense to the human, and the other one is to develop a product that appeals to the market (Österlin, 2011). In this project both of this areas are part of the objective.
4.2 PLANNING The current project process started with reviewing the project objectives: what the limitations were, what resources that was available and the time limits. In the project, a brief was used to clarify and describe the task. For making a time plan of the workflow in the project a Gantt chart was developed (see in appendix 1).
12 4.2.1 The brief
When the client company meets with the designer and provides information about the project, it is generally referred to as a brief. In the current project, the brief was written down and the document served as a guiding document during the entire design process (Österlin, 2011). The document was written so that that everyone involved in the project, or on parts of it, agreed about the tasks to be solved. It was important to be accurate in the preliminary work made in this stage, and to let it take some time because it is considered to be the easiest and cheapest way to affect in what direction the project is going. It also was to increase the likelihood of high quality work lather on. The most important aspect of the start-up was to avoid misunderstandings later in the project. Having the projects goals clearly defined before the project started was in this project the key (Österlin, 2011). The intention was that a comprehensive and detailed brief should spell out what was needed to be done and with what constraints. In the brief, the objectives and the project goals was defined without specifying a fixed solution. In addition, such documentation can be used as a project description and the basis for quotations, if the company decides to outsource the work to designer companies (Österlin, 2011).
The director of Primary & Concept Development, Husqvarna Group and the company supervisor were responsible for holding the brief. By studying the report written in the prior project (Gustafsson & Karlsson, 2014), the author in the current project started up the development work for the new tool belt. The background was that way clarified in detail. Together with what were stated in the brief, a document was written in the same template that the other engineers from the department use when starting up a new project. Known as a knowledge brief. See figure 11 and in full scale in appendix 1.
Figure 11. The project brief (also found in appendix 1). 13 The brief included a background that explained the starting points, for example that an extensive analysis of the market already had been executed, and that a new solution for attaching the holsters to the belt had been developed. From a competitive position, the reason for the current project was stated as that competitors from other tool belt industries are beginning finding their way into the market of tool belts for forestry. The target group was to be included in the design process, to secure that the belt was developed with their needs in focus: i.e. for the professional forestry workers. The vision for the tool belt, with an underlying objective of what the company would gain from the project, was stated as:
“It will be the best on the market and customers will buy the product because of the design, function and ergonomics. It will potentially increase sale up to 114%”1
In short, what to be achieved was to develop an ergonomic tool belt with a new design, new materials and to integrate the technical solutions that were developed prior to this project and reintroduce a version of an older popular belt buckle solution. Also, to in the end have five functional prototypes of the new tool belt professionally manufactured.
The brief also included a to-do list: . Collaborate with Smart Textiles, Borås university and its textile district to investigate possible textile materials . Collaborate with Husqvarna brand designer Rajinder Mehra to develop the design . Produce drawings and all the material specifications
After all involved had reviewed the project brief document, some small changes were made and the documentation was approved, and this became the formal start of the project.
4.2.2 Gantt chart For making a time plan for the workflow in the project a Gantt chart were used. The Gantt is a classic tool used for project management that can be used for a wide range of types of projects (Wilson, 2003). Such charts are used for time and timing of tasks.
The horizontal bars represent the working stages: the length of them represents the time needed for the task and the bars also have date for the start and end of each task. The Gantt chart often have tasks that run parallel under a time period but the author choose not to set it up this way for the reason of having a clear date for when the task, or activity, needed to be finished to ensure a good end result. See the Gant chart used in figure 12 and also in appendix 2.
1 Personal communication Alexander Persson, Husqvarna Accessories (Autumn 2014) 14 Figure 12. Gantt chart used in project (also in appendix 2).
Since other engineers also were involved and worked parallel with the belt project, and because that the belt had to be ready for field testing in the end of the project, the schedule were also made to include the work of the engineers developing the new belt buckle and the new holsters, as seen in appendix 2. The reason for doing so was that their work with the belt buckle and holsters would be ready in time for manufacturing. The planning was not meant for them to strictly follow, but more of a suggestion.
In the beginning of the project, the author’s knowledge of what textiles, plastics foams and webbings etc. that were appropriate for such outdoors conditions that the belt would be exposed to, were poor. Also, this was the case for the engineers inside the company. Most of the accessories, such as clothing and harnesses, are produced elsewhere, and sub-contractors manufacturing the Husqvarna products set the material selection for most part. This is the reason for that the longest bar is for the activity of searching appropriate materials. The main parts of the project were planned to deal with ergonomical fit, choise of material and the industrial design of the whole composition of the belt. Figure 13 visually communicates the time spent on these different areas, and visualizes the fact that they sometimes interferred with each other.
Figure 13. A visual representation of the time spent on different parts in the project. 15 4.3 COLLECTING INFORMATION In the current project, several methods were used to collect information: interviewing experts and non-experts in various areas, prototyping the experience of the workers environment, interviewing forestry workers about their needs, and observing how they currently use the belt, further described in upcoming sections.
4.3.1 Experiencing prototyping A prototype is in general seen as a representation of an artifact before it exists, and can range from sketches to models at various levels. Using prototypes gives an insight of how it will be like to interact with the product that is being designed. "Experience prototyping" is a form of prototyping where active engagement with prototypes gives an understanding of existing or future conditions the product will be faced with, according to Buchenau and Fulton Suri (2000). In the product development process experiencing prototyping can be used in several stages of the design process: especially for understanding existing experiences, exploring design ideas, and interaction of design concepts. The ones to interact with the prototypes can be team members, users and clients.
The experiencing prototyping method was first used for better understanding the experience of using the current product within its context. The information gathered was about what the user, in this case the author, sees, feels, and hears. But the data collected goes beyond the sensory system, also at what role an artifact serves within the context. Houde and Hill (1997) define the role as "the functions that an artifact serves in a user’s life — the way in which it is useful to them." By using the method of “Experiencing prototyping” described by Buchenau and Fulton Suri, 2000 witch is a representation that is designed for understanding and, exploring how it is like to like to engage with the product. The author of this project got to experience the workers environment and get a deeper understanding of the tool belt and its application. The author of this project first used the method by being out in the field and using the tool belt for its purpose, see figure 14. Experiencing prototyping is more than just doing the work, the experience is not carried out in a vacuum: it is full of other things like how the environment is like, the terrain, the weather and temperature. Also, in the current case the feeling and weight of the equipment. The current tool belt is used for felling, limbing and bucking trees. For a better understanding of the product and what forestry work is like for the workers that use the tool belt in their profession, the current author wanted to experience real forestry work and understand how to use the tools. Both observing and participating in some of the tasks in forestry work, such as e.g. felling, limbing, and bucking trees, was intended to be experienced. In figure 14, the author is seen using a chainsaw to cut the branches of the tree, a task called limbing.
16 Figure 14. The author limbing a tree, during experience prototyping.
The whole activity of experiencing the forestry work was carried out right before the actual project started. For this task the tool belt, safety equipment and clothing were borrowed from Husqvarna. What was understood during the experience prototyping was that this is an extremely physical strenuous and demanding work. Actually, just walking around in the terrain with all the equipment was exhausting for the author. In terms of wearing the tool belt and how it felt in an ergonomically sense, could not be evaluated. This was because of all the other impressions of exhaustion, wearing the helmet, the visor that reduced the eyesight, and the protective earphones giving the feeling of disconnect from all that was going on around you. Although the ergonomics of the belt could not be evaluated, the activity gave a valuable insight in the experience of forestry work, and the output from it were of great importance for the continued project. One conclusion was that the ergonomics of the belt could easier be evaluated in a less strenuous situation, and without wearying too much of the distracting safety equipment.
4.3.2 Interviews The method of interviewing is one of the most basic form of collecting data and it is a versatile method that can be used for a broad range of situations (Bohgard et al., 2011). By carrying out interviews you generally want to gather information about what people think and their ideas, goals, and aspirations.
17 Also interviews give knowledge about people’s experiences, knowledge, values, their opinion and attitudes (Bohgard et al., 2011). According to Bohgard et al. the interview method can be divided into three categories unstructured, semi structured, and structured. The purpose of the interview determents which of the categories to use. Generally the structured interview is to prefer for gathering quantitative data and the unstructured interviews for gathering qualitative data (Bohgard et al.). In the current project, questions were written down beforehand, but when carrying out the interview new questions arise which made most of the interviews that were made semi structured. The information gathered in this project was largely based on interviews, not just in the beginning, but also throughout the whole project. Wherever there was someone who had knowledge beneficial to the project, an interview was performed. In the current project this involved interviews about the belt and forestry work, or companies that manufacture materials, and retailers of material that could be used for the belt. This involved that the interviews were both semi-structured and unstructured. It was for this reason beneficial to the author to have a desk and working on site at Husqvarna and hence be able to talk to people whenever information was needed. Information gathering in this sense were performed in unstructured interviews; such as informal conversations with colleagues, or with the personnel in the Test lab located downstairs from the author’s desk.
There are also various methods for collecting the data during the interview. In the current project, note taking, audio recordings and photography were used. According to Bohgard et al. (2011), one of the most commonly used methods for documenting interviews are handwritten notes. In this perspective, the interviewer should strive to capture some of the everyday verbalism from the interview. The notes, if they are transcribed right after the interview, can give a description that is very close to an actual transcript (Bohgard et al., 2011). In the author’s view, to make audio recording is a very easy activity, but transcribing the recordings into text can be very time consuming. Another disadvantage is that the recording can be intimidating for the one that is being interviewed. While interviewing a specialist in the field and former professional forester, who nowadays are a consultant to Husqvarna, an audio recording was made. This later turned out as one of the most important interviews in the project. The audio recording made sure that no information were lost, and made it possible to revisit the recording over and over again, which was valuable.
Another experience from the project is that taking pictures after or during an interview makes it easier to remember the situation and what was said. An example where pictures were taken was at an interview at FOV Fabrics AB, see figure 15, in Borås, Sweden. The company produces and develops high technology woven fabrics. In this interview notes were taken as well as pictures.
18 Figure 15. Visit at F.O.V Fabrics AB for material selection. Another example where the method of taking pictures was very useful was at a trade show for subcontractors in the manufacturing industry. It was an annual fair held at Elmia in Jönköping, Sweden that brought around 1,200 exhibitors from 30 countries, see figure 16 for pictures from the fair visited during autumn of 2014.
Figure 16. Elmia Subcontractor fair, visited in autumn 2014.
By luck, this huge fair that is northern Europe’s leading trade show for subcontractors, were held in Jönköping during the time this thesis project was being executed. It was a good opportunity to talk to contractors in the plastics foam and webbings industry. Material that was identified during this fair was also later used in the final belts. In total, around 15 interviews with including notes, video-recordings and/or picture-takings, were performed during the project.
19 4.3.3 Husqvarna’s current belts The holsters that Husqvarna sells today, see figure 17, are adapted to fit both the wider belt se figure 18, and a normal waist belt see figure 19. The holster is fastened to the wider belt by using screws. There are forestry workers that still use just a leather belt. For these belts the holsters are threaded on, holsters from other forestry brand and also the Husqvarna holsters are adapted for these belts. When interviewing professional forestry workers, a wider belt was said to be more comfortable than the normal waist belt2. For this reason, by making a belt wider in the back and around the hips the weight of the belt from the tools will be spread out on a larger area, which will make the belt more comfortable and ergonomic. Additionally, the perceived weight of the belt is experienced as less3. The normal waist belts have a tendency to chafer, and are overall less ergonomic and comfortable to wear, according to the forestry workers. The wider belt was said to provide back support.
Figure 18. Wide belt from Husqvarna.
Figure 17. Holster from Husqvarna. Figure 19. Normal waist belt from Husqvarna.
4.3.4 Think-Aloud Protocol Within usability testing, think-aloud methods have become a popular method. The method is very successful to use when evaluating functionality of an application (Martin & Hanington, 2012). The method is a way to collect verbal data while a participant performs a task. The participants are asked to verbalize whatever they are looking at, feeling, doing and thinking as they are performing a specified task. Martin and Hanington describes that ‘Think-aloud protocols’ are divided into two experimental methods. When the data is collected during the task at hand the procedure is called ‘Concurrent Think-aloud’. This is the most commonly used way. The other procedure is called ‘Retrospective Think- aloud’ and the secession is here recorded in silence by a video-tape or with a screen capture device commonly used in interface design. After the task is completed the participants are asked to watch the recordings and comment their approach, which is thought to give insight into the participants reasoning,
2 Personal communication, Forestry workers (autumn 2014) 3 Personal communication, Forestry workers (autumn 2014) 20 intentions and implemented strategies (Martin & Hangington, 2012). For the current project, a more informal and interactive think-aloud method were used, compared to the one described by Martin and Hanington. The intention of using the method was to evaluate competitor’s belts such as forestry and carpentry tool belts. In the test setup six different belts were evaluated, see figure 20, by six participants. The test subject ether had experience in forestry and was a current user of the belt or had no experience of forestry at all. The traditional approach to the think-aloud method by reading a neutral instruction script in the beginning of each session, were implemented. This was in order to avoid biasing influence in the participant’s verbalization of their experiences.
Husqvarna, current belt
Snickers XTR
Fristads Snikki Ergo belt
Prototype (Gustafsson & Karlsson, 2014)
Toughbuilt
Stihl
Figure 20. Competitors belts used in Think-aloud session.
The instructions in the script was that the participant were asked to try on each of the belts and while doing so verbalize whatever they were looking at, feeling, doing and thinking as they are performing the task. To mimic some of the positions the forester holds, the participant were asked to squat and imitate picking up something heavy from the floor. To make the task less intimidating for the participants so that he or she would freely say anything they actually were thinking of. Added in the script was also that nothing that they say was “right” or “wrong” and that what is important are what each participant think about the belts. The verbal data was collected by taking notes. The implementation of the ‘think aloud method’ was in the current project an approach to benchmarking competitor’s products. After a couple of test 21 rounds, a pattern emerged in the sessions in regards to what the participants said about the belts: similar statements started to appear. The information received in the think-aloud protocol were of the qualitative sort. From the statements of participant’s experiences of the various belts and the observations the author made while conducting the test. Subsequently, this became a good information source for the Product requirement list. An interesting reflection is that the observations that were made of the participant’s handling of the various belts were in the current project almost equally as important as what was actually said during the performance of the tasks.
4.4 BENCHMARKING Benchmarking is a method to systematically compare, evaluate and learn from good role models (Österlin, 2012). The purpose is to get insights and knowledge about similar products. Hence, the method can be described as a “civilized” way of industrial espionage. To actually receive information and understand what can be improved by the benchmarking method, it is said to be easier to implement some kind of quantitative measurable data, to be able to compare the different brands (Österlin, 2012). The information and result of the information from benchmarking is both qualitative and quantitative. Quantitative in the sense of the measurable data such as price, materials standards, number of details, and so forth. The previous mentioning of implementation of the think aloud method by listening to people testing the belts, also gave some qualitative information about their experiences of using the belts.
4.4.1 Benchmarking brands The same belts used for the think aloud activity were further benchmarked, see figure 21. The participants that contributed in the think-aloud activity also took part in the benchmarking activity. The previous think-aloud method was not just beneficial for gathering user needs and demands, but the belts were
Husqvarna, current belt Snickers XTR Fristads Snikki
Prototype Toughbuilt Sthil (Gustafsson & Karlsson, 2014)
Figure 21. Competitors belt from benchmarking activity. 22 already known by the participants, which made it easier for them to compare the belts. In the benchmarking activity, a total of eight participants gave their understanding and insight about the parameters that were compared. These were aspects such as 1) the fit of the belt, 2) comfort, 3) movability, 4) sense of quality, 5) sense of robustness, and 6) the industrial design. These parameters were chosen to better understand what makes the belt ergonomic, what material to use, and what kind of design the test persons preferred. The test belts, see figure 21, in the benchmarking were rated from a scale to from 1-5, and where 1 was not good at all and 5 was a very good user experience. See the results in appendix 4.
4.4.2 Benchmarking shape and ergonomics -experiencing form To understand how the shape of the belt correlated, and the ergonomic aspects of the belt, a new benchmarking setup were made. The belts from the previous benchmarking activity were also used here, but this time only the shape of the belts were evaluated. Since there were two straight-formed belts and two with the current Husqvarna shape, the number of belts for this test was narrowed down to four. To just evaluate the shape of the belt, and nothing else, it was necessary to eliminate properties like materials and overall construction of the different belts. The belts were therefore all prototyped in the same materials, and the also the length of the backside were made the same for all the belts. Figure 22 illustrates the shapes of the belts that were tested. The belts for this
Figure 22. Shape of belts that were tested in benchmarking. benchmarking activity were made out of sleeping mattresses for the back piece. A webbing strap were used in the front and a plastic side release buckle were placed on the side of the back piece since this will be where the new extendable belt buckle is supposed to be placed (a prerequisite based on Husqvarna’s project
23 brief, see appendix 1). To evaluate how different shapes of the belt feels with the weight from the tools, Velcro tape was used to attach the holsters including the tools, see figure 23. In this benchmarking activity, only the shapes relation to ergonomics were of interest so the parameters that were compared and rated were the 1) fit of the belt, 2) comfort, and 3) movability which were rated on a scale from 1-5 (1 not good, 5 very good). See the results in appendix 5.
Figure 23. Illustrates the prototypes of belts that were tested in the benchmarking activity.
4.4.3 Summary of benchmarking and think-aloud Test results from the think-aloud were of the qualitative sort. The two benchmarking test gave quantitative measurable data see appendix 4 and 5. The first the benchmarking test when the test persons tried on the actual competitor’s belts, the belt that got the far best results of the parameters concerning ergonomics fit, comfort and freedom of movement, were the current Husqvarna belt. The belt that had the lowest scores was the Snickers XTR Tool belt. When just the different shapes of the brands were benchmarked, the Snickers XTR Tool belt got the best result, and the current Husqvarna belt came in second. These tests results indicate that the materials are of great importance for the ergonomics of the belt. From the think-aloud protocol a lot of the remarks of the Snickers XTR belt was that it was “too stiff and thick”. The remarks on the Husqvarna belt were that “it was good” and that it was “more flexible” compared to some of the others, and that it was “slim”.4 The shape of the Husqvarna and the Snickers belt are very different and quite reverse when it comes to the width of the belt. The Snickers belt is narrow in the back, and that is exactly where the Husqvarna belt is widest se figure 25. Secondly, were the Snicker belt is widest is the Husqvarna belt getting narrower. The following work of developing concept for the shape is based on these two belts.
4 Statements from participants in the think aloud activity (Autumn 2014) 24 Snickers XTR
Husqvarna
Snickers XTR
Husqvarna
Figure 25. Illustrating the two belts that got best test results.
4.5 LITTERATURE REVIEW To gather information about methods and overall knowledge of relevant areas and theories, a broad literature review about ergonomics and product design and related areas were studied. Some of the literature was course literature from the Industrial Design Engineering program, and some was new books and scientific articles. As the project proceeded the literature review got more focused on specific topics. Primo, the LTU library search engine, containing the libraries collections of printed and electronic material were mostly used, but also Google Scholar reviewed material were used. In the beginning of the project, the keywords for searching relevant literature were for example ergonomics, ergonomic design, product design and usability. It was also useful to look further into literature referenced in peer-reviewed articles. The LTU academic supervisor was also a big help when finding references to methods to use in the project for more specific tasks, such as for example experience prototyping, think-aloud protocols.
4.6 PRODUCT REQUIREMENT LIST The knowledge collected in the project has been the basis for setting up the Product requirement list. The requirement list is a set of demands and wishes that determine the solution and embodiment of the product (Paul & Beitz, 2004). The requirement list served as a guiding line in the current project and as an analysis of how the solution met the requirements. A first preliminary list was set up early in the product design process. This preliminary list was based on requirements identified in the product-planning phase. The document has thereafter been continually reviewed, and as the design process proceeded it has grown and changed. The requirements are either demands or wishes.
25 Demands are in this view requirements that must be met. If these requirements are not fulfilled the solution is not seen as acceptable. Wishes are in this view requirements that shall be fulfilled if possible and give added value to the product. The Product requirements that were identified for the belt comes from the all of the interview gathering activities, such as interviews, think-aloud protocols and benchmarking. The requirement list is divided into subcategories depending on the type of function that the requirement applies. The criteria are divided into the subcategories and can be seen in figure 24.
Figure 24. Product requirement list. 26 4.7 IDEA DEVELOPMENT A lot of the basis for the development of an ergonomic belt for forestry workers came from the extensive analysis and collecting of information in the beginning of the project. This made it quite clear how the forestry belt could be designed, but that does not exclude that there are other working solutions or principles for the belt. In general, the meaning of the creative process during the idea development phase is to be open for new ideas (Österlin, 2012). Since an idea of the belt already existed, the method of the Scamper brainstorming technique (see e.g. von Boeijen et al., 2014) were used to produce alternative solutions. This was done to better ensure that no groundbreaking alternative or detail solutions were forgotten in the process.
From the observations, when the participants were trying on the belts in the think-aloud protocol activity and the benchmarking activities, a problem with current belts was identified. The belts that were wider in the back never gave any close contact with the body. Instead there were gaps over the back area. For this reason, the idea came that it was unnecessary for the belt to be wide in the back and better for the belt to be wider around the hips and over the back pelvic, where the belts gave a better contact. Looking at the anatomy of the body, the hips are places where the body have more muscles and naturally more fat, so for the tool belt to be wider here, and to spread the weight of the tool belt over this area will better ensure that the tool belt is adapted to the human anatomy, see figure 26. Therefore, such a solution could ensure the criteria of the belt’s ergonomic fit.
Figure 26. Illustrating human anatomy and an ergonomic the fit of a belt.
In order to come up with ideas of a good shape for the belt, the easiest way was seen as to make small paper prototypes, see figure 27. Also, varying properties of the two shapes that got the best result in the benchmarking gave ideas of different shapes.
27
Figure 26. Illustrating the idea generation of shapes.
4.7.1 The Scamper technique The principles of the Scamper Brainstorming Technique, also known as ‘Osborns idésporrar’ in Swedish, is inspired by Alex F. Osborn, but includes an expansion of his Brainstorming method (Eberle, 1996). The Scamper technique is usually set as a method of using idea-spurring questions (von Boeijen et al., 2014). Based on something that already exists, the questions hence are to spur new ideas, by suggesting some addition or modification of the original idea. In the current project, the implementation of the Scamper method resulted in a number of new ideas, see figure 27. According to Eberle, the acronym SCAMPER stands for:
S — Substitute (e.g., components, materials) C — Combine (e.g., mix, combine with other assemblies, and integrate) A — Adapt (e.g., alter, change function, use part of another element) M — Magnify/Modify (e.g., change in scale, change shape, modify attributes) P — Put to other uses E — Eliminate (e.g., remove elements, simplify, reduce to core functionality) R — Rearrange/Reverse (e.g., turn inside out or upside down)
28
Figure 27. Ideas from using the Scamper method.
4.8 SEARCHING FOR WORKING PRINCIPALS After the idea development, the work with searching for working principles began, further described in coming sections.
4.8.1 Textile tool belt The Snickers XTR tool belt has several layers of foam and textiles, see figure 28. The previous solution for attaching holsters is built on the same principle as the Snickers XTR belt for attaching holsters (Gustafsson & Karlsson, 2014).
Snickers
Figure 28. Illustrating the working principle of the Snickers XTR belt.
4.8.2 The current Husqvarna belt The outside of the current belt, see 29, is made of a plastic material called high density polyeten: HDPE. This specific plastic have been used erlier for stretchers in the military (Gustafsson & Karlsson, 2014). The benefits of this material are that it is tough and robust and handles the stains of the harsh
29 environment very well. The foam that is on the inside of the belt is a low-density polyethylene: LDPE, see figure 29. It is used for the cushioning effect that gives comfort to the belt. The thickness of the materials is 1 mm HDPE and 5 mm of the foam. The foam has closed cells and is good for use in outdoor products since it doesn’t absorb water. There are also foams that are more commonly used for everyday products with open cells, this foams absorb a lot of water and are not suitable for outside use. 5
Figure 29. The wide Husqvarna belt.
4.8.3 Husqvarna’s harness for forestry clearing saws The harnesses for forestry clearing saws are exposed to the same environment as the tool belt. The textile that is used around the waist in the Husqvarna
Figure 30. Illustrating the Husqvarna harness and the belts fabric.
Balance XT harnesses are a Nylon fabric with a Polypropylene (PP) coating, see figure 30. This coated textile have no breathability. It’s totally waterproof and the thick coating makes the weight heavy. The textile is coarsely woven witch gives it a lot of texture. This means that dirt penetrates and get packed into the weave. The materials feels robust and strong, but there are textiles that is stronger, waterproofs and still light6.
5 Personal communication with test lab personnel at Husqvarna (Autumn 2014) 6 Personal communication with textile material experts (Autumn 2014) 30 4.9 CONCEPT DEVELOPMENT The work with the tool belt continued, and in the upcoming section the concept development methods are further described.
4.9.1 Prototyping When developing the belts shape, full-scale prototypes were made. The first prototypes were made in paper, which was a very easy way to go about. The different shapes of the belt were drawings made in a computer software and then printed in full scale. These paper prototypes were tested by having co- workers from Husqvarna to hold up the paper belt and it was then easy to see how well it followed the body contour. When finding a shape that fit the bodies of the co-workers, belts were made in the same material as the current belt and also equipped with a belt in front. The co-workers on the department at Husqvarna were of all different sizes; from small to more robust; and one of them were actually two meters tall so they were of a wide range of sizes. Therefore, they were found to be perfect to evaluate the prototypes on.
Figure 31. Illustrating the belt prototypes.
In the process of developing the shape a number of aspects were of importance: . The area of the body it covers . The size . How conical the belts were, which should make the ends of the back piece line up in the front . A good fit: meaning that the belts had contact with the body and were not gaping
To have the right length or size means that the place for the first two holsters closest to the front have to be placed on the side of the thighs. This was done for a couple of reasons: the holsters should not hinder the foresters in his or hers work, when the forestry worker bend down the holsters cannot be in the
31 way and that the tools are easiest to reach when placed on the side of the thighs. If the belt is to short the holsters will end up further back and then harder to reach. The question of having different sizes of the belt were not investigated further because it seemed that one size fitted all test-persons (which were of varying sizes as previously mentioned).
As for the area of the body it covers, the conclusion was that it was better to have the belt wider where the body naturally has more muscles and fat. For the belt to have contact around the body it must be conical to follow the body contour otherwise the belt will gap. The belt becomes conical if the upper length is shorter than the lower edge, see figure 32. All of this was confirmed by trial-and-error during the prototyping of the belts.
Figure 32. Illustrating the conical belt. 4.9.2 Construction of the belt When the holsters are attached onto the belt the structure should be stable enough so that it doesn’t cave when the holsters are hanged onto to the belt. Therefore, it was concluded that a stabilizing layer of the belts assembling parts should be included. A layer of a cushioning material was also seen necessary for the comfort of the belt. All of this was tested with different materials and the prototyping gave information of how the experience should be. In a meeting with the brand manager the new belt was decided to be a textile belt, a strong robust textile was seen necessary for the outside and another textile for the inside. It was identified that the lower and upper straps can be sewn over the outside textile and through the stabilizing layer. Then the layers of the cushioning material, the inside textile, outside textile and the structure upholding material will be sewn together. To cover the edges, some material usually a strap of some kind of webbing, can be used. This is standard for when a textile belt is sewn together, and the edges are covered with a strap or webbing of some sort. But for the belt that is developed the author wanted achieve a soft edge around the belt for a higher comfort level. The cushioning material is cut out so it will be a bit larger than the harder stable material, see figure 33. This means that two types of material can be used to cover the edges, and for the harder stabilizing material, the edge can be covered with a strong and high visibility fabric. Webbing can cover the softer cushioning material, and after that the two pieces can be sewn together.
32 Figure 33. Illustrating the edges of the belt and how the different materials can be sewn together (in Swedish).
4.9.3 Exploring alternatives for ventilating properties One requirement for the belt was for it to have high ventilating properties. Therefore, a sewn pattern through the softer material and the inside textile can create ventilating channels so that the heat and moisture from the body will not be closed in. A couple of alternatives were explored, se figure 34.
Holes
Vertical Honeycomb Metal wires lines pattern patterns
Figure 34. Illustrating different ways to create ventilating channels.
33 4.9.4 Materials in context In Sweden the forestry work is seasonal and not performed during late spring to early autumn, due to the heavy physical workload that transforms into body heat. The gear and amount of protective equipment is also not suited for warm climates. That the work field is seasonal means loss of production during these months, and to make the season longer would probably be more profitable for the forestry companies. When developing the current tool belt, the author for this reason was striving to increase thermic comfort. Thermal comfort or discomfort depends on the thermal environment, activity level and heat-, and moisture transfer properties of the textile. The work wear such as the jacket is waterproof but still allows the material to breath. The textile closest to the body, to increase thermal comfort should have the same properties and allow heat loss through perspiration and evaporation. Also the material should allow some friction against the jacket so that the belt stays in place and doesn’t slide. To achieve friction a textured yarn can be used to get a perforated textile and the more coarsely woven the textile is, the more friction between the fabrics. Opposite of the textured yarn is a smother yarn and the finer the weave is the more dirt repelling the textile becomes.7 The materials especially on the outside of the belt must be robust, have high cut and abrasion resistance and also repel dirt.
4.9.5 Innovation Expo in November, 2014 The department at Husqvarna have an annual Innovation Expo where they present the projects that they are currently working on. Other departments within the company are invited to experience ongoing primary development projects, to comment, discuss and try out prototypes. This is for marketing ideas and spread knowledge about new technologies, using DNA boards and test working prototypes. The intent of the Expos is to create a broad forum for discussing innovations cross-category, and to facilitate the transfer of technologies over organizational borderlines. The Expo also promotes the department. The director of Primary & Concept Development wanted the project for developing the new tool belt for Pro users to also take part in this Expo8. Since it was held on the 5th of November 2014, and the project was due over a month later, on the 19th of December, the author was still in the process of developing the shape of the belt and researching materials. However, a few weeks before the Expo the Husqvarna brand manager wanted a full scale drawing of the shape of the belt, so that he had something to work from when designing the visual appearance, and also to make some suggestions of colours and materials, see figure 35.
7 Personal communication with textile material experts (Autumn 2014) 8 Personal communication, Husqvarna (Autumn 2014) 34
Figure 35. The visual appearance and material suggestions of the final belt design, developed by the Husqvarna Brand manager.
The consequent belt that the Husqvarna Brand manager developed the visual appearance for is in the colors of grey and orange. These are the colors that the Husqvarna brand now uses, quite different from the previous blue and orange. However, as can be seen in figure 36, the belt that subsequently was created for the Expo had black webbing instead of grey. This was due to that you have to make a costly and large order of materials to have the fabric dyed in the color that you want. For the Expo, see figure 37, the author had to use colors that the supplier had in stock. When manufacturing the belts for the Expo the author therefore used the textiles and fabric that had previously been ordered to test different materials. Out of these materials the author made the choice to the use the most robust materials for the belt that have previously been stated in the product requirement list. The prototype was fully functional and developed to withstand the harsh environments that the forestry work requires. As can be seen in figure 36, the final prototype made for the Expo was not as bent as the previous visualizations and drawings. This was because the webbing straps that hold the holsters in place were too stiff to be able to be sewn that way, therefore the belt had to be adapted, and made with a straighter outline.
Figure 36. The final prototype made for the Innovation Expo in November, 2014
35 Figure 37. The author with the final belt design at the Innovation Expo.
4.9.6 Iterating experiencing prototyping To evaluate if the quickly manufactured prototype from the Expo was the best solution and had the most ergonomic shape, new prototypes were made. These prototypes were made by varying one thing, about the Expo belt, at the time, and also the current Husqvarna belt was included, se figure 38. Again the two belts that got the best results in the benchmarking were used and based on their differences, variations of the Expo belt was made. In total five belts including the current Husqvarna belt were manufactured and the back pieces were this time made out of the material used in the current Husqvarna belt. A webbing strap were used in the front and a plastic side release buckle were placed on the side of the back piece. The belts manufactured were complete with holsters and tools, see figure 39. This time users of the current belt participated in the test. Husqvarna have their own Quality Assurance Team (QA). The QA-team tests products and prototypes in the field. As in the case of testing a product like the tool belt, they have an actual forest area to be harvested in order for the test situation to be as realistic as possible 9. The work that is carried out is no different from them being a team of professional forester’s workers, except that they are told to pay extra attention to the experience of the gear. The same
9 Personal communication with QA team at Husqvarna (Autumn 2014) 36 parameters as in the benchmarking of shape were evaluated, that is: the fit of the belt, the comfort and the freedom of movability. The parameters were rated from 1-5 by four participants, see appendix 6. Included in the questionnaire handed to the QA team were questions like what was positive/negative? And what could be improved? The comments were that it was quite difficult to evaluate the different belts because of the similarity of the belts, and that some liked it better when the belt covers the back. See result in appendix 5.
Figure 38. Illustrating new experience Figure 39. Illustrating the working prototypes. prototypes.
4.9.7 Computer modeling For visualization and creating drawings the company standard program Catia V5 and their application for Computer aided design (CAD) was used. Catia is developed by French Dassault Systems and can be used through the whole product development process with use of applications for Computer Aided Manufacturing (CAM) and Computer Aided Engineering (CAE) 10 . In the current project the software was used for:
. Part Design: for visualization and creating 3D-modells (see figure 40) . Drafting: for creating 2D drawings (see figure 41)
The benefits to use the company CAD system and work with solid modeling was that it was easy to reach and insert the assembly of the belt buckle, so that the belt could be adapted after the dimension of the belt buckle. The company used and saved all of their work in SmartTeam for their product data management, so therefore it was easy to reach drawings, and other parts, as well as material specifications of the Husqvarna products of interest for this work.
10 http://www.3ds.com/products-services/catia/ 37 Figure 40. The belt design was modeled in 3D.
The company that helped to sew the belt was a small two-man family business located in Jönköping. They did various kinds of work like changing and repair of original furnishings of vintage cars. They also help and perform prototype work on car interiors for the automotive industry. Since they only needed the drawings in a scale of 1:1, because they cut out the drawings and used them as templates, there are no measurements or tolerances on the drawings, see figure 41. With the drawings they also got an A3 picture of the belts front and back, as can be seen in figure 42.
Figure 41. Illustrating the 2D drawing of the belt. 38
Figure 42. Illustrating the modeled Tool belt design.
39 5 Results This chapter describes the project results, from the different project phases. As the previous Methods and implementation chapter was chosen to communicate the whole design process as much as possible, the result chapter only describes a brief summary of the results.
5.1 CONTEXT RESULTS From early information gathering and context analysis, performed through the previous-mentioned methods the think-aloud method, the benchmarking and from the interviews, it was established that a belt made for forestry needs to be narrow in front of the belts so that it won’t hinder the forester bending over squatting. The work context is the nature, and instead of adjusting the workplace to the human, the worker in this case must adjust to the work environment, with often uncomfortable and non-ergonomic working positions as a result.
The first the benchmarking test when the test persons tried on the actual competitor’s belts, the belt that got the far best results of the parameters concerning ergonomics fit, comfort and freedom of movement, were the current Husqvarna belt. The belt that had the lowest scores was the Snickers XTR Tool belt, see results in appendix 4. When just the different shapes of the brands were benchmarked, the Snickers XTR Tool belt got the best result, and the current Husqvarna belt came in second, see results in appendix 5. From the benchmarking of brands and shape tests results indicate that the materials are of great importance for the ergonomics of the belt. From the think-aloud protocol a lot of the remarks of the Snickers XTR belt was that it was “too stiff and thick”. The remarks on the Husqvarna belt were that “it was good” that it was “more flexible” compared to some of the others, and that it was “slim”.11
By making a belt wider in the back and around the hips, the weight of the belt from the tools will be spread out on a larger area. This will make the belt more comfortable, ergonomic and the perceived weight of the belt will be less. This was the reason for the final belt shape. However, there are forestry workers that still use a leather belt. The Husqvarna holsters are adapted for this. The advantages for these belts are that the user can customize the belt and combine holsters from other brands as well. In Gustafsson and Karlsson’s (2014) previous study, there were a strong demand for more holsters from the Husqvarna brand and that is a reason why users turns to other brands that have the holsters they want. In communication whit a professional user, in this case a farmer that makes his living out of the forest and have been in the forestry field for around 50 years. The conclusion from this interview was that from his experience
11 Statements from participants in the think aloud activity (Autumn 2014) 40 leather belts have a tendency to chafer and are overall less ergonomic and uncomfortable to wear12. He now uses the wider belt from Husqvarna and from his experience wider belt is more comfortable and that the perceived weight from wearing the belt is be less. This confirmed the new belt shape.
5.2 RESULTS OF IDEA AND CONCEPT DEVELOPMENT As previously mentioned, in Sweden forestry work is seasonal and not performed during late spring to early autumn due to the heavy physical work that transforms into body heat. When developing the current tool belt, the materials combination and design should strive to increase thermic comfort. The conclusion of all the various materials and prototype testing previously described was that especially the outside of the belt must be robust, have a high cut and abrasion resistance and also repel dirt.
5.3 RESULTS OF DETAIL DEVELOPMENT Since the belt is sometimes left outside during the night or when the forestry worker is working while it is raining the belt will be wet. Therefore there can be no materials in the belts construction that absorbs water. The outer textiles must therefore be water-resistant. Since the belt is sewn together a problem that can happen is that the seams puncture the textiles and water could enter into the construction of the belt. Therefore to choose only textiles that is totally waterproof can make the belt difficult to dry out and later start to mould and smell. Because of this the textile on the outside for the new belt is totally waterproof, but the inside material is a water repellent textile that can still breathe. This will make the belt easier to dry out.
5.4 FINAL RESULT Figure 43 shows the final Tool belt design, see also figures 47-48. All of the materials especially on the outside were chosen for their high abrasion and cut resistance. On the inside other properties were also of importance, for example, the inside textile needed to be textured to give friction against the jacket so that the belt will stay in place. And for thermic comfort and ventilating properties a Cordura was chosen, it’s a textile often used in workwear. The textile is treated to be water-resistant but still breathable. A small lining of fluorescent polyester was also included on the inside to make it visible in the surroundings if the forester takes off the belt.
Textiles used on the outside were a waterproof and reinforced textile with Vectran named Techsteel and a PVC coated textile that is fluorescent, to make it stand out in nature. All of the webbing straps are made out of polyester (PES), often used in outdoor product. The buttons that were chosen were also made for outdoor products.
12 Personal communication whit experienced Pro User (Autumn 2014)
41 Figure 43. The final Tool belt design.
To make the belt so that it doesn’t cave in from the weight of the holsters a Thermoplastic Polyolefin (TPO) material was chosen for its structure upholding properties. It’s a material that is excellent for outside use and big users of TPO are sports and leisure goods. This particular TPO is laminated with a 2 mm Polyethylene (PE) foam, see figure 44.
Figure 44. Illustrate the foam laminated TPO material
For the material that give cushioning and comfort a 3 mm Polyethylene (PE) with a textile laminate was chosen, see figure 45. The textile is on the inside of the belt so when the chosen honeycomb pattern is sewn thru the foam the seams won’t cut thru the foam because of the textile. Both of the foams, the foam laminated to the TPO and the textile laminated foam have closed cells so they do not absorb any water.
Figure 45. Illustrate the textile laminated 3 mm PE foam used in the belt to make it comfortable.
42 The concept of attaching holsters was adjusted to use a strap sewn onto the belt in the lower edge, to hang the holster on. To secure the holsters another strap sewn in the upper edge are fowled over the lower strap and attached by snap fasteners. This new concept makes it easy to change the holsters and the forester can easily adjust the belt for different work assignment in the forest, see figure 46. For a more comprehensive description of chosen materials, see appendix 3, 7-10.
Figure 46. Illustrates the concept of attaching holsters.
Figure 47. Final Tool belt design with all holsters attached
43 Figure 48. Images illustrating the belt’s detail designs, and the final design "in action".
44 6 Discussion In this final chapter the author discuss the master thesis project result in relation to the implemented method and theory.
6.1 RELEVANCE According to Åstrand and Rodahl (1988), forestry and logging work is highly demanding, and as they continue: it is probably one of the final physically demanding jobs left in the industrialized world. Even though this was stated back in 1988, the motor-manual work with the use of chainsaw has not changed much, which the literature review confirmed. By using the method of experiencing prototyping, as described by Buchenau and Fulton Suri (2000), the author experienced the workers environment and got a deep understanding of how extremely physical demanding the job actually is. Using the method quite early in the project, in combination with knowledge gained in the education in Ergonomic design, shaped the following work. The meaning of what an ergonomic belt for this type of work, needed to be explored. The understanding of the forestry work was also made through the literature study, primarily about the hazards of forestry work. Many of the studies showed that the lower back area is most commonly reported area for musculoskeletal problems (i.e. Gallis, 2006). High forces on the disks in the lower back can over time give long-term problems (ibid.). The example of biomechanics showed that even moderate burden in a position where a person just slightly reached out (in comparison to the forestry workers postures), gave a result that exceeded NIOSH value for safe loads (Bohgard et al. 2011; Dempsey, 2002). The positions and movements the forestry workers with the load of the chainsaw can therefore easily double the NIOSH value for safe loads. The very base in ergonomics and working life is how to arrange the work to fit the human (Bohgard et al. 2011; Dul & Weerdmeester, 2002, IEA, n.d.). In the case of forestry work the human need to adapt to nature, the weather and following working positions that the trees and grounds provides. Based on the literature study the author’s conclusion is that motor-manual work in the forest is hazardous and unfit for humans to execute. The best thing for humans would probably be to not do this type of forestry work, however, this was not part of my project, but instead to improve gears used in forestry work.
When interviewing professional forestry workers many said that they wanted a belt that gave support for the back. Knowing the background of how hazardous this work is for the lower back, the area of back belts was thoroughly investigated through both a literature review and also in contacting with an expert occupational therapist. The result was that back belts do not prevent injury. Moreover, the back belts used in medical health care that actually gives support for the disks in the lower back, hinder movement and are unsuited for forestry work. What a back belt can give is pressure, and for a forestry worker with back pain this will give comfort, but also a false sense of security. What the forestry worker actually needs, and the only thing that can help, is rest. This
45 was the reason behind the choice of the belts shape. Another insight gained from the project was that it is good to plan a project, but the planning never comes true. All different things happened along the way and every plan had to change. The Expo was a very good experience, which certainly resulted in a finished prototype for showing and testing. This was very valuable in hindsight, but very trying at the time due to short lead-time.
Also, in the beginning of the project it was decided that the in-house project at Husqvarna should develop new holsters parallel to the current project. These holsters were then supposed to be used for the new tool belt. In reality the holsters were not finished. A new design was developed for the belt buckle and for the due date of the project one prototype were produced in polyamide by Selective Laser Sintering (SLS). This was not due to laziness in any sense, but because that other projects they were working on had a higher priority. The belts were completed a couple of weeks after the project for this thesis. The belt buckles were made in aluminum. The holsters were a combination of the pockets from the carpenter belt Snickers XTR and Husqvarna’s holsters to fit the belt, see figure 46 and 47. The belts were later tested in field tests.
The design of the tool belt is a process the author have learned a lot of participating in. The value and understanding gained from all the iterations and prototyping, the search of “perfect” materials, all in all it gave a lot of knowledge of how to develop products. For this kind of product and what it is used for this was a very good process, and something I find very valuable to have been part of.
6.2 RECOMMENDATION Some final recommendations for future work with this concept. Robustness was the prime goal together with the ergonomics of the belt. Robustness of materials can be compromised depending on where on the belt the material is situated. For example the most robust textile that was found were used on the outside of the belt. But for the inside, friction against clothing and breathability can compromise the robustness of the material, also the material on the inside is less exposed to tearing.
Another recommendation is to use high quality textiles, usually the higher the quality the better it repels dirt and also have less tendency to get bleached. Since the new belt is a textile belt the thought of making a washable belt was one idea. Therefore the manufacturers and suppliers of all of the textiles, foams, webbing, and plastics included in the final belt were all asked the question if the material is washable and at what temperature. The answer was that all of the materials used can be washed for certain at 40° but probably even up to 60°. So the recommendation for further work is to see if there is a need to have a washable belt since the materials needed for the belt actually is washable.
46 A further recommendation is to the use a Husqvarna orange textile on the outside, to make the belt even more visible since visibility is highly important when several foresters are out working as a team over a forest area or close to the road. The Techsteel textile, see figure 49, that was used on the outside of the belt is made out of 18% Vectran, which is extremely strong, this is the reason why this textile is one of the most robust and cut resistant textile material on the market and the best choice for this application. The Techsteel textile seen in the sample in figure 49, is partly white because Vectran is extremely difficult to dye. The black color is a dyeable Cordura textile which is a high quality polyamide. So if the Cordura textile is dyed into Husqvarna orange it would become an orange and white fabric which can be a nice effect to use together with the grey webbings that the brand manager set for the belt. This recommendation is an approach to make a more visible belt in grey and orange which are also the colors of the Husqvarna clothing line.
Figure 49. Illustrates the Techsteel material
A recommendation is also to use some kind of reflective material to make the belt stand out in the forest. An example is to use a reflective textile, like the one shown in figure 50, which looks quite neutral while looking at it, but it reflects light as shown below. During the season that the foresters work it gets dark fast especially in the winter months. This textiles will reflect the light from the forestry machines or cars going by if working close to the road. The material
Figure 50. Illustrates a reflective material.
47 in the example is blue but this is also a dyeable Cordura textile. Also this textile is made with Vectran, the one in the example is made with 4% Vectran. The belt cannot improve the hazards of forestry work, so it is recommended that forestry workers get some information about ergonomics before they enter the field. Another consideration is to use more foam for a better cushioning effect. When choosing the materials for the inside of the belt a TPO polymer laminated with 2 mm foam was chosen to uphold the structure of the belt. The thought was to use the TPO on the outside and the foam on the inside. What happened was that when the seamstress tried to sew the outside textiles and webbing strap pocket for the holsters the textile got wrinkly. But when turning the TPO the other way so that the 2 mm foam was between the outside textile and the TPO material the result gave a nice effect to the whole belt and there was no wrinkling of the textile. So a recommendation for further development is to use a stiffer material to uphold the whole structure of the belt and use a foam between the stiffer matererial and the outer textile. The negative effect of turning the TPO around was that instead of having 5 mm foam for cushioning and comfort just the 3 mm foam that was left inside the belt. For this reason a thicker foam on the inside is probably needed. The 3 mm foam was sewn together with the textile on the inside in a honeycomb pattern so that the seams in this pattern would create air channels but by using just the 3 mm foam it didn’t really give the deep air channels wanted. So by choosing a thicker foam the honeycomb sewn pattern will probably be more apparent and have deeper channels.
48 References Bohgard, M. (red.) (2011). Arbete och teknik på människans villkor. (2. Uppl.) Stockholm: Prevent Buchenau, M. & Fulton Suri, J. (2000) Experience Prototyping. In proceeding of DIS’00, 3rd conference on Designing interactive systems: processes, practices, methods and techniques, pp. 424-433. Chen, C-Y, Chen, L-C & Lin, L. (2003) Methods for processing and prioritizing customer demands in variant product design. IIE Transactions, Vol. 36, No. 3, pp. 203-219 Dempsey, P. G. (2002). Usability of the revised NIOSH lifting equation. Ergonomics, Vol. 45, No.12, pp. 817-828 Dul, J. & Weerdmeester, B.A. (2001). Ergonomics for beginners: a quick reference guide. (2. Ed.). London: Taylor & Francis Gallis, C. (2006) Work-related prevalence of musculoskeletal symptoms among Greek forest workers. International Journal of Industrial Ergonomics Vo. 36 (2006), pp. 731–736 Geraldi, J (2012) Gantt charts revisited a critical analysis of its roots and implications to the management of projects today. International Journal of Managing Project in Business. Vol. 5 iss 4 pp. 578 – 594. Available at: http://dx.doi.org/10.1108/17538371211268889 (2015-02-03) Gustafsson, R., & Karlsson A. (2014). Tool belt for professional forestry workers. BSc thesis. Jönköping: Jönköpings Tekniska Högskola. Harstela, P. (1990). Work postures and strain of workers in Nordic forest work: A selective review. International Journal of Industrial Ergonomics, Vol. 5, No.3, pp. 219-226. Haubner, P. J. (2007) Ergonomics in industrial product design. Ergonomics, Vol. 33, No. 4, pp. 477-485 Houde, S., and Hill, C. (1997) What Do Prototypes Prototype? In Handbook of Human-Computer Interaction (2nd Ed.), M. Helander, T. Landauer, and P. Prabhu (eds.): Amsterdam: Elsevier Science Husqvarna group. (n.d.). Client company’s internal web page. Retrieved 2014- 10-08, from http://www.husqvarnagroup.com IEA International Ergonomic Association (n.d.) Definition of Ergonomics. Available at http://www.iea.cc/whats/index.html (2015-06-09) Martin, B. & Hanington, B.M. (2012). Universal methods of design: 100 ways to research complex problems, develop innovative ideas, and design effective solutions. Beverly, MA: Rockport Publishers Pahl, G & Beitz, W. (2007) Engineering design: a systematic approach. London: Springer
49 Pontén, B. (1988). Health risks in forestry work: a report for action. Report No. 177, Department of Operational Efficiency, College of Forestry, Sweden Swedish Work Environment Authority. (2012). Användning av motorkedjesågar och röjsågar. (AFS 2012:01). Stockholm: Elanders Gotab AB. Retrieved 2014-10-11, from: http://www.av.se Swedish Work Environment Authority. (2012). Skogsbruk, korta arbetsskadefakta. (AFS 2012:03). Stockholm: Elanders Gotab AB. Retrieved 2014-10-15, from: http://www.av.se Tague, N.R. (2005). The quality toolbox. (2nd ed.) Milwaukee, Wis.: ASQ Quality Press Van Boeijen, A. Daalhuizen, J., Zijlstra, J. & van der Schoor, R. (eds) (2014) Delft Design Guide: Design Methods. Delft University of Technology, Faculty of Industrial Design Engineering. Amsterdam: BIS Publishers Wilson, J. M. (2003) Gantt charts: A centenary appreciation. European Journal of Operational Research, Vol. 149 (2003), pp. 430-437 Åstrand, P. O, & Rodahl K. (1988) Textbook of Work Physiology. (3rd ed.). McGraw-Hill Österlin, Kenneth (2011) Design i fokus för produktutveckling. Malmö: Liber
50 Appendices
Appendix 1 – Project brief Appendix 2 – Project time plan Appendix 3 – Materials and companies Appendix 4 – Benchmarking brands Appendix 5 – Benchmarking shape and ergonomics-experiencing Appendix 6 – Iretating experiencing prototyping Appendix 7 – Textiles for the outside Appendix 8 – Textiles for the inside Appendix 9 – Foams and 3 mesh spacer fabric Appendix 10 – Construction upholding materials Appendix 11 – 3 mesh spacer fabric Appendix 12 – TPO Appendix 13 – Webbings
1
Appendix 1 – Project brief
Appendix 2 – Project time plan
Appendix 3 – Materials and companies
F.O.V Bandi Cordura Syntetband polyester Art. 93314F Art.13–66519 F.O.V Svart Bredd 19 mm Fluorescerande polyester Färg 001, Svart Art. 8209MF Bandi Färg Gul Oelastiskt polyesterband Art.13 –48850 Bredd 50 mm Fä rg 001, Svart
Bandi (en underrem) Oelastiskt polyesterband Art.13 - 48835 Bredd 35 mm Färg 825, Ljusgrå
Wasa Tryckknapp Art. 101
Bandi F.O.V Oelastiskt Techsteel, 18% Vectran Rex rep Rex rep polyesterband Art. 94406HH Syntetband polyester Resår latexvarp Art.13–48840 Svart Art. 2575-12mm Bredd 20 mm Bredd 40 mm Bredd 12 mm Färg Svart Färg 001, Svart Färg Svart F.O.V Inuti Fluorescerande PVC Art. 66836-PM430 Gislaved folie AB TPO 0,7mm +PE 2mm (foam) Art. 8705 Figuren visar det framtagna bältet, dess material och vilket företag de kommer ifrån.
Dafa PE 3mm (foam) + Textil laminat 33kg/m ³ *Alveolit
Appendix 4 – Benchmarking brands
Tabellen visa resultat från benchmarking av olika företags skogs- och snickarbälten.
Appendix 5 – Benchmarking shape and ergonomics-experiencing form
Figuren visar form på prototyper som tillverkades för att göra benchmarking av enbart form på olika företags verktygs bälten.
Tabellen visar resultatet från benchmarking av form på olika företags verktygs bälten.
Fristads Husqvarna Snickers XTR Sthil/Thoughbuilt Snikki Passform 3.5 3.9 2.8 3.1 Komfort 3.5 3.8 2.8 3.5 Rörlighet 4 4.4 3.6 4.1
Appendix 6 – Iterating experiencing prototyping
1
2
3
4
5
Figuren visar prototyper som tillverkades då olika parametrar varierades utgående ifrån bältet som togs fram till företags Expot. Även Husqvarnas aktuella bälte ses.
Tabellen visar resultatet då ovanstående prototyper testades av Husqvarnas Quality Assurance team. Bälte 1 2 3 4 5
Passform 3,75 4 4,5 4 3,75
Komfort 3,5 3,5 4,5 3,75 3,75 Rörlighet 3,75 4 4 4 4,25
Appendix 7 – Textiles for the outside
PA (Polyamid) Nylon®, Cordura® PU (Polyurethane) PES (Polyester)
Figuren visar textilier som togs fram som möjliga val av material till utsidan av bältet.
Från vänster 1) Cordura + Vectran 4 % (Reflekterande) DWR +PU-membran Bra nötegenskaper och riv motstånd
2) Cordura + Vectran 18 % DWR +PU-membran Varunamn: Techsteel, materialet är en Liquid Crystal Polymer. Extremt bra nötegenskaper och riv motstånd
3) Polyamid Bionic-membran Används i polisjackor
4) Nylon Polypropen beläggning Textil som används i Balance XT selar
5) PVC belagd Polyamid (Fluorescerande) Bionic-membran Används i bojar, varningstrianglar Mycket goda nötegenskaper’
Appendix 8 – Textiles for the inside
PA Polyamide / Nylon®/Cordura PU Polyurethane PES Polyeseter DWR Durable water repellent PP Polypropylen
Figuren visar textilier som togs fram som möjliga val av material till insidan av bältet.
Från vänster 1) Cordura: grovt texturerat garn DWR behandlad Arbetskläder
2) Cordura: finare texturerat garn DWR behandlad Arbetskläder
3) Nylon Polypropen beläggning Textil som används i Balance XT selar.
4) Polyester (Fluorescerande) Arbetskläder
Appendix 9 – Foams and 3 mesh spacer fabric
Figuren visa skum och mesh material som togs fram som möjliga val av material för att ge komfort till bältet.
Från vänster 1) PE 3 mm (foam) 28 kg/m³
2) PE 5 mm (skum) 33 kg/m³ *Sensaten R30
3) PE 4 mm (skum) 67 kg/m³ *Sensaten XE 15
4) PE 4 mm (skum) 67 kg/m³ *Sensaten XE 15
5) PE 3 mm(skum) 33 kg/m³ *Alveolit
6) 3 mesh spacer fabric Art. 7810 thickness 6,5 mm Figuren visar ett 3mm textil laminerat PE-skum.
7) Textil laminerat PE 3 mm (skum) 33 kg/m³ *Alveolit
Appendix 10 – Construction upholding materials
Figuren visar plaster och skum som togs fram som möjliga val av material för bältets formstabilitet.
Från vänster 1) TPO 0,7mm +PE 2 mm (skum) *Kvalité 8705 (Gislaved folie AB)
2) TPO 0,7mm *Kvalité 8705 (Gislaved folie AB)
3) PE 1.5 mm (skum) 185 kg/m³ *Alveolit
4) PE 3 mm (skum) 150 kg/m³
5) PP 0,5 mm (plast ark)
6) PE 1mm (plast ark)
Appendix 11 – 3 mesh spacer fabric
Sampels of spacer fabric from Muller texitiles. Aricel number and thickness from the left: Art. 6004 thickness 3,0 mm, Art. 7810 thickness 6,5 mm, Art. 5948 thickness 10,0 mm,Art. 6013 thickness 10,0 mm
Figuren visar prov på 3mesh spacer material.
The 3D mesh spacer fabric is used for its cushioning effect and high air permeability 3mesh spacer fabric is fabricated by using a warp knitting technique. When varying the construction of the two outer layers and the pile yarn in between the hardness of the material can be adjusted. 3 mesh spacer can be used as an alternative to textiles, foam, net, lining, and as well as for leather and artificial leather
Figuren visar prov på 3mesh spacer materia. 3D mesh advantages: . Extremely high air distribution in all directions – even under pressure . Low emission (VOC+FOG value) . Soft cushioning effect . Very low weight . Enormous forming property and contour flow . Recyclability . Long product life . Comfort surface feel . Good lamination qualities
Appendix 12 – TPO TPO är en termoelast (TPE) och består av PE, PP blandat med ett gummimaterial (EPDM). Materialen har god mekanisk hållfasthet och tål utomhusanvändning. Anledningen är att EPDM är ett utmärkt gummimaterial för utomhusbruk
Köldtålig uppvisargoda egenskaper och slagtålighet även vid låga temperaturer (-25°). Sport- och fritidsartiklar är stora användare av TPO
I figuren nedanför ses prover på TPO från Gislaved Folie AB. Det blå TPO materialet har en tjocklek på 0,7mm och det svarta är av samma material men laminerat med ett 3mm PE-skum.
Figuren visar prov på TPO material samt material specifikation.
Appendix 13 – Webbings Webbings are usually made of ether polyester, polypropylene nylon or cotton. Cotton and nylon material stretches when it gets wet, therefore the webbings that are usually used in outdoor products are made in polyester (PES) or polypropylene (PP). Polyester has better UV-resistance and holds the color longer without getting bleached. Polyester has high abrasion resistance and holds an overall better quality than polypropylene. The downside is that it is more expensive and heavier than polypropylene. The current Husqvarna products, such as e.g. the harnesses for clearing saws, are made out of polypropylene due to the lower price.1
The webbings that were chosen for the belt are from a company in Sweden that produces webbings/straps of a high quality. All of the webbings used in the belt are made of polyester (PES), based on the discussion above.
Figuren visar prov remmar i polyester.
1 Personal communication with the company Bandi (Autumn 2014)